* add: legend modification parameters and output DPI
This commit adds a CLI parameter to plot_histogram in order to position
the legend of the plot on the diagram.
It also defines the output DPI for the plot to 600 dpi.
Plot_progression gets a CLI paramter to add a custom label and to
overwrite the default one.
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Co-authored-by: dbv <jt@dbv03.linpro.no>
Co-authored-by: dbv <spreadcat.github@micronarrativ.org>
